Method of magnetic-ore separation



UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF LLEWELLYN PARK, NEW JERSEY.

METHOD OF MAGNETIC-ORE SEPARATION.

SPECIFICATION forming part of Letters Patent No. 485,842, dated November8, 1892.

Application filed July 20, 1892. Serial No. 4%,637. (N0 specimen.)

To all whom it may concern:

Be it known that I, THOMAS A. EDISON, a citizen of the United States,residing at Llewellyn Park, in the county of Essex and State of NewJersey, have invented a certain new and useful Improvement in TreatingOres,

(Case No. 958,) of which the following is a specification.

The object of this invention is to produce an effective and economicalmethod for the treatment of low-grade nickeliferous pyritous ores, so asto recover the nickel therefrom and also the cobalt, gold, copper, andother metals or metallic ores that may be present.

I have discovered that where magnetic pyrites, called pyrrhotite, isnickeliferous, as it usually is to a more or less extent, the nickel isnot distributed generally throughout the Whole body of the pyrrhotite,but certain crystals are pure pyrrhotite or magnetic pyrites, whileother crystals have some of the iron replaced by nickel and sometimes bycobalt, and that the crystals containing the nickel or cobalt areconsiderably-less magnetic than the pure pyrrhotite.

In carryingout myinvention I proceed as follows,assuming the ore tocontain nickeliferous pyrrhotite or magnetic pyrites, chalco-pyrites orcopper pyrites, withgold, &c: I first grind the Whole of the crude ore,so as to eliminate the pyrrhotite, gold, &c., from the worthless gangue.The crushed ore is then concentrated by jigging orvanning orbyanyotherappropriate concentrating method, thus giving a concentratecontaining the nickeliferous pyrrhotite, gold, blende, and galenawithout any material quantity of quartz or other worthless matter. Thisconcentrate is then passed through a magnetic separator which is capableof working wet ores, or the concentrate isdried and passed through amagnetic separator adapted to work dry ores. The magnetism is soregulated that only the particles of magnetic pyrites which contain nonickel or cobalt are acted upon, the magnetism being too weak to drawaway the less magnetic or nickeliferous pyrrhotite. After the purepyrrhotite has thus been separated the remainder of the concentrate isrun through a more powerful magnetic separator, which withdraws thenickeliferous pyrrhotite, leaving all the other or non-magneticmaterials. The nickeliferous pyrrhotite which is obtained in this way,although small in quantity compared with the whole amount of ore, willbe sulficiently rich to be put into a matte by the regular methods. Theremainder of the concentrate is then roasted in a closed cylinder withslight access of air, it desirable, to render the copper pyritesmagnetic, when the magnetic copper pyrites may be withdrawn from therest of the material by a magnetic separator, as explained in my patent,No.465,250. After the copper pyrites have been withdrawn from theconcentrate the remainder, containing the gold, silver, zinc, lead, &c.,of the original ore, is worked in the wet way or matted and workedelectrolytically, as will be well understood.

What I claim is- 1. The process of separating nickeliferous fromnon-nickeliferous pyrrhotite where both occur in the same ore,consisting in subjecting the crushed material to a magnetic action ofsuch strength that, due to the diiference in magnetic capacity of thenickeliferous and non-nickeliferous pyrrhotite, the non-nickeliferouspyrrhotite will be acted upon magnetically, while the nickeliferouspyrrhotite will not be thus acted upon, substantially as set forth.

2. The process of treating ores containing nickeliferous andnon-nickeliferouspyrrhotite, consisting in first crushing the ore tofree the particles ofipyrites from the gangue and other metals, passingthe material through a magnetic separator of a sufficient strength towithdraw all the magnetic pyrites, and then passing the magnetic pyritesthrough another magnetic separator having a sufiicient strength to actupon the non-nickeliferous pyrrhotite, but not upon the nickeliferouspyrrhotite, substantially as set forth.

This specification signed and witnessed this 9th day of July, 1892.

THOS. A. EDISON.

Witnesses:

RICHARD N. DYER, EUGENE CONRAN.

